1. Field of the Invention
This invention relates to a digital still camera equipped with a display unit for displaying the image of a subject and with a composition assist function, and to a method of controlling operation of the camera.
2. Description of the Related Art
When a beginner takes a picture, the subject often is placed in the center of the imaging area. Images obtained by such photography therefore have a monotonous composition. And when a person is photographed with scenery as the background, the person often appears too small.
Thus, a beginner who is not accustomed to taking pictures with a camera does not possess a skilled photographic technique.
Accordingly, an object of the present invention is to improve the photographic technique of a beginner who is not accustomed to taking pictures.
According to the present invention, the foregoing object is attained by providing a digital still camera equipped with a composition assist function, comprising: an imaging unit for sensing the image of a subject and outputting image data representing the image of the subject; a display unit for displaying the image of the subject represented by the image data output from the imaging unit; a display controller (display control means) for controlling the display unit so as to display assistance lines, which are for deciding composition for the purpose of taking a picture of the subject, in a form superimposed on the image of the subject being displayed on the display unit; and a recording controller (recording control means) responsive to depression of a shutter-release button for recording the image data, which is output from the imaging unit, on a recording medium.
The present invention provides also a method of controlling operation of the camera described above. Specifically, the present invention provides a method of controlling operation of a digital still camera equipped with a composition assist function, the camera having an imaging unit for sensing the image of a subject and outputting image data representing the image of the subject, a display unit for displaying the image of the subject represented by the image data output from the imaging unit, and a recording controller (recording control means) responsive to depression of a shutter-release button for recording the image data, which is output from the imaging unit, on a recording medium, the method including a step of controlling the display unit so as to display assistance lines, which are for deciding composition for the purpose of taking a picture of the subject, in a form superimposed on the image of the subject being displayed on the display unit.
In accordance with the present invention, the image of a subject is displayed on the display unit. The aforementioned assistance lines for deciding the composition of the picture are displayed in a form superimposed on the image of the subject being displayed on the display unit.
While observing the assistance lines being displayed on the display unit, the user decides the composition of the subject in such a manner that the subject is disposed in accordance with the assistance lines. Even a beginner, therefore, can use freely a variety of photographic techniques. By repeating photography in accordance with the assistance lines while the assistance lines are being displayed on the display unit, even a beginner can acquire a variety of photographic techniques.
A single assistance line may be used, or the assistance lines may define a frame which indicates the placement of the subject.
The camera may further include a display command switch for applying a command to display the aforesaid assistance lines. In such case the display controller displays the assistance lines on the display unit in response to the display command applied by the display command switch.
The assistance lines can be displayed when they are necessary. Thus, it can be so arranged that annoying assistance lines are not displayed for a user who has acquired photographic technique.
The camera may further include a display control command switch for applying a command that is for the purpose of controlling the display unit. In such case the display controller responds to a first command from the display control command switch by turning the display unit on to display the image of the subject, responds to a second command from the display control command switch by displaying the assistance lines in a form superimposed on the image of the subject, and responds to a third command from the display control command switch by turning off the display unit.
Thus, the on/off state of a display on the display unit and display of the assistance lines can be controlled using the display control switch.
The camera may further include a move-command input unit for inputting a command to move the position at which the assistance lines are displayed. In such case the display controller responds to a move command entered from the move-command input unit by displaying the assistance lines upon moving them.
Thus, the user can move the assistance-line display position as necessary.
In a case where the shutter-release button is capable of being pressed through first and second stroke lengths, the display of the assistance lines is presented on the display unit in response to depression of the shutter-release button through its first stroke length, and the image data output from the imaging unit is recorded on the recording medium in response to depression of the shutter-release button through its second stroke length.
Thus, display of the assistance lines can be controlled in response to depression of the shutter-release button. The shutter-release button is pressed through its first stroke length when the composition is to be decided. Consequently, the assistance lines are displayed on the display unit in order to decide the composition at such time that the shutter-release button has been pressed through its first stroke length. When the composition is decided in accordance with the assistance lines, the shutter-release button is pressed through its second stroke length so that the image data representing the image of the subject will be recorded on the recording medium.
The camera may further be provided with adjustment means for performing at least one of exposure adjustment and focus adjustment based upon image data representing an image within an area specified by the assistance lines.
Since the photographic composition is decided in accordance with the assistance lines, it is construed that the main subject lies within the area defined by the assistance lines. Because processing such as exposure adjustment and focus adjustment is executed based upon the image data representing the image within the area specified by the assistance lines, exposure and focus adjustment suitable for shooting the main subject can be realized.
In a case where the camera is further equipped with a strobe for illuminating the subject with auxiliary light and the assistance lines displayed on the display unit define a frame for portrait photography, it is desired that the frame for portrait photography be displayed on the display unit in a relationship identical with the positional relationship of the strobe disposed on the front side of the camera.
In case of portrait photography, the head of the person serving as the main subject is at the top of the picture. If the main subject is shot while the digital camera is held vertically or horizontally, the strobe may be situated at the bottom. If the strobe is situated at the bottom, the strobe light will illuminate the subject from below and cause a shadow to be cast on the main subject.
When the frame for portrait photography is displayed on the display unit, the frame for portrait photography assumes a relationship identical with the positional relationship of the strobe on the front side of the camera. When the frame is displayed at the top of the display screen of the display unit, the strobe also will be at the top on the front side of the camera. By deciding the composition in such a manner that the face of the person who is the main subject falls within the frame for portrait photography, the strobe light will illuminate the main subject from above. This makes it possible to prevent a shadow from being cast on the image of the main subject.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.